The present invention relates to a device for expanding a uterocervical canal of a fertilized animal and removing a mucus attached to the canal.
Generally, a cow has only 7 to 8 calves through life. For this reason, recently, a method for mass-producing superior cows in a short period by embryotransfer has been adopted to obtain a large number of cows having good blood lines behind them, a good construction and good capabilities.
Usually, recovering of embryos of cow used for transplanting is carried out by inserting a balloon catheter having many side holes in the tip portion thereof into the uterus of a cow about seven days after embryogeny and drawing embryos together with a perfusate introduced into the uterus through the catheter.
A large quantity of a mucus is present in the cervical canal of a cow about seven days after embryogeny. Therefore, when the balloon catheter is inserted into the uterus horn at such time, the mucus enters into the side holes of the balloon catheter so that the side holes are choked with the mucus, which results in difficulty in collecting embryos.
Heretofore, a rod for expanding a cervical canal as shown in FIG. 4 was used to expand a cervical canal and to remove the mucus therein. However, the mucus in the cervical canal was hardly removed by such conventional method using the cervical canal-expanding rod. Accordingly, when the balloon catheter was inserted into the uterus horn to collect embryos, the side holes of the catheter were choked with the remaining mucus and it was often difficult to collect embryos.
Embryos drawn from the uterus together with the perfusate are filtered through a wire net having a size of opening of about 70 .mu.m to remove the perfusate and collected on the wire net. When the mucus is not removed sufficiently from the cervical canal in advance, the perfusate drawn from the uterus is frequently get mixed with the mucus. When such perfusate is filtered by using the wire net, the embryos remain on the wire net in such state that they are enclosed in the mucus, which causes an decrease of embryo-collecting rate.
It is an object of the present invention to provide a device for expanding a uterocervical canal of a fertilized animal and removing a mucus attached to the canal, which is capable of efficiently removing a mucus present in the canal.
This and other objects of the invention will become apparent from the description hereinafter.